Thinning fruit trees

When I took a fruit tree pruning workshop last fall, the organic commercial growers there described their maintenance regime. One thing they emphasized, was thinning fruit about 6-8 weeks after bloom when the fruit is very small . Thinning down to one per cluster.
This produces larger fruit that they believe are much more marketable. Also that it creates less stress to the tree than a huge bumper crop. Thereby making it more likely the tree will produce every year instead of a huge crop one year, then skipping a year the next.
For all of you with fruit trees May/ June is the time to thin here. It might already have passed this opportune time for you.